1. Technical Field
The present invention is related to a device for reducing cavernous resonance generated in a pneumatic tire and a pneumatic tire provided with the same. More specifically, the present invention relates to a tire noise reduction device that makes both a reduction of manufacturing costs and an improvement of durability possible, and a pneumatic tire provided with the same.
2. Related Art
In pneumatic tires, cavernous resonance caused by the vibration of air that the tire is filled with is one cause of noise being generated. When a tire is rolled, uneven road surfaces cause a tread portion to vibrate. The vibrations of the tread portion cause the air inside the tire to vibrate which causes cavernous resonance to be generated.
Providing a noise absorbing member made from a porous material on an entire circumference of an inner surface of the tread portion of a pneumatic tire has been proposed as a technique for reducing noise caused by cavernous resonance.
When the noise absorbing member made from the porous material is formed into a band and this noise absorbing member band is disposed along the inner surface of the tread portion of a pneumatic tire, at least one of the ends thereof comes in direct contact with a tire inside surface. For example, when both ends of the noise absorbing member band are butted against each other, both ends come in direct contact with the tire inside surface. Additionally, when both ends of the noise absorbing member band are overlapped, one of the ends comes in direct contact with the tire inside surface. When such an end of such a noise absorbing member band is in contact with the tire inside surface, the end of the noise absorbing member rubs against the tire inside surface during tire rotation. Therefore, a problem exists in that the noise absorbing member is prone to damage starting at this area where the noise absorbing member rubs against the tire inside surface.
On the other hand, it is possible to form an annular noise absorbing member that does not have ends in a tire circumferential direction in place of the noise absorbing member band. There is merit in this case in that the noise absorbing member is not easily damaged. However, it is necessary to form such an annular noise absorbing member for each tire size. Therefore, there is a problem in that the manufacturing costs of the tire noise reduction device will increase significantly.
An object of the present invention is to provide a tire noise reduction device that makes both a reduction of manufacturing costs and an improvement of durability possible, and a pneumatic tire provided with the same.